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Jason Shaw

2009-Feb-12 19:31 UTC

[R] Extending each element in a list, or rbind()-ing arrays of different length without recycling

Hi,

I'm trying to take a matrix such as

     [,1] [,2] [,3] [,4] [,5]
[1,]    2    7    2    7    9
[2,]   10   10    6    8    6
[3,]    1    9    7    2    0

and generate a new matrix which contains only the unique values in each row:

     [,1] [,2] [,3] [,4] [,5]
[1,]    2    7    9   NA   NA
[2,]   10    6    8   NA   NA
[3,]    1    9    7    2    0

My problem is that I can use apply(matrix,MARGIN=1,FUN=unique) to find
the unique values, but this leaves me with a list with arrays of
different length:
> x <- apply(peaks,MARGIN=1,FUN=unique)[[1]]
[1] 2 7 9

[[2]]
[1] 10  6  8

[[3]]
[1] 1 9 7 2 0

and using do.call("rbind",x) recycles the values of the shorter
vectors instead of filling them with NA:
> do.call("rbind",x)     [,1] [,2] [,3] [,4] [,5]
[1,]    2    7    9    2    7
[2,]   10    6    8   10    6
[3,]    1    9    7    2    0

So, I'd like to either take every element of the list and extend it
with NAs to the length of the longest element, or rbind every element
where missing places are filled with NAs instead of recycled values.
Is this possible?  Of course, the solution is trivial using a loop,
but I'm trying to avoid this.

Thanks for any suggestions.

Jorge Ivan Velez

2009-Feb-12 19:40 UTC

head link

[R] Extending each element in a list, or rbind()-ing arrays of different length without recycling

Dear Jason,
Try this:

x<-matrix(scan(),byrow=TRUE,ncol=5)
2    7    2    7    9
10   10    6    8    6
1    9    7    2    0

res<-apply(x,1,unique)  # Unique values
maxlength<-max(do.call(c,lapply(res,length)))   # Maximum length of unique
values

# Your matrix
do.call(rbind,lapply(res,function(x){
             x[maxlength]<-NA
               x
             }
       )
)


HTH,

Jorge


On Thu, Feb 12, 2009 at 2:31 PM, Jason Shaw <jason.shaw.23@gmail.com>
wrote:
> Hi,
>
> I'm trying to take a matrix such as
>
>     [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    2    7    9
> [2,]   10   10    6    8    6
> [3,]    1    9    7    2    0
>
> and generate a new matrix which contains only the unique values in each
> row:
>
>     [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    9   NA   NA
> [2,]   10    6    8   NA   NA
> [3,]    1    9    7    2    0
>
> My problem is that I can use apply(matrix,MARGIN=1,FUN=unique) to find
> the unique values, but this leaves me with a list with arrays of
> different length:
>
> > x <- apply(peaks,MARGIN=1,FUN=unique)
> [[1]]
> [1] 2 7 9
>
> [[2]]
> [1] 10  6  8
>
> [[3]]
> [1] 1 9 7 2 0
>
> and using do.call("rbind",x) recycles the values of the shorter
> vectors instead of filling them with NA:
>
> > do.call("rbind",x)
>     [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    9    2    7
> [2,]   10    6    8   10    6
> [3,]    1    9    7    2    0
>
> So, I'd like to either take every element of the list and extend it
> with NAs to the length of the longest element, or rbind every element
> where missing places are filled with NAs instead of recycled values.
> Is this possible?  Of course, the solution is trivial using a loop,
> but I'm trying to avoid this.
>
> Thanks for any suggestions.
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

markleeds at verizon.net

2009-Feb-12 20:06 UTC

head link

[R] Extending each element in a list, or rbind()-ing arrays of different length without recycling

Hi Jason: below seems to work. you have to take the transpose because 
the apply
returns the rows transposed. i'm also not sure how to make the NAs be 
the last
ones but maybe someone can show us how to do that.

mat <- matrix(c(2,7,2,7,9,10,10,6,8,6,1,9,7,2,0),byrow=TRUE,nrow=3)
print(mat)

t(apply(mat,1, function(.row) {
   .row[duplicated(.row)] <- NA
   .row
}))




On Thu, Feb 12, 2009 at  2:31 PM, Jason Shaw wrote:
> Hi,
>
> I'm trying to take a matrix such as
>
>      [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    2    7    9
> [2,]   10   10    6    8    6
> [3,]    1    9    7    2    0
>
> and generate a new matrix which contains only the unique values in 
> each row:
>
>      [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    9   NA   NA
> [2,]   10    6    8   NA   NA
> [3,]    1    9    7    2    0
>
> My problem is that I can use apply(matrix,MARGIN=1,FUN=unique) to find
> the unique values, but this leaves me with a list with arrays of
> different length:
>
>> x <- apply(peaks,MARGIN=1,FUN=unique)
> [[1]]
> [1] 2 7 9
>
> [[2]]
> [1] 10  6  8
>
> [[3]]
> [1] 1 9 7 2 0
>
> and using do.call("rbind",x) recycles the values of the shorter
> vectors instead of filling them with NA:
>
>> do.call("rbind",x)
>      [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    9    2    7
> [2,]   10    6    8   10    6
> [3,]    1    9    7    2    0
>
> So, I'd like to either take every element of the list and extend it
> with NAs to the length of the longest element, or rbind every element
> where missing places are filled with NAs instead of recycled values.
> Is this possible?  Of course, the solution is trivial using a loop,
> but I'm trying to avoid this.
>
> Thanks for any suggestions.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

Gabor Grothendieck

2009-Feb-12 20:16 UTC

head link

[R] Extending each element in a list, or rbind()-ing arrays of different length without recycling

Try this.  After the apply from your post we use lapply
to make each series into a zoo series so that we can later
use zoo's multiway merge.  Finally we actually merge them
and in the next statement just makes nice column names:
> library(zoo)
> all3 <- do.call(merge, lapply(apply(peaks, 1, unique), zoo))
> colnames(all3) <- make.names(1:ncol(all3))
> all3  X1 X2 X3
1  2 10  1
2  7  6  9
3  9  8  7
4 NA NA  2
5 NA NA  0


On Thu, Feb 12, 2009 at 2:31 PM, Jason Shaw <jason.shaw.23 at gmail.com>
wrote:> Hi,
>
> I'm trying to take a matrix such as
>
>     [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    2    7    9
> [2,]   10   10    6    8    6
> [3,]    1    9    7    2    0
>
> and generate a new matrix which contains only the unique values in each
row:
>
>     [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    9   NA   NA
> [2,]   10    6    8   NA   NA
> [3,]    1    9    7    2    0
>
> My problem is that I can use apply(matrix,MARGIN=1,FUN=unique) to find
> the unique values, but this leaves me with a list with arrays of
> different length:
>
>> x <- apply(peaks,MARGIN=1,FUN=unique)
> [[1]]
> [1] 2 7 9
>
> [[2]]
> [1] 10  6  8
>
> [[3]]
> [1] 1 9 7 2 0
>
> and using do.call("rbind",x) recycles the values of the shorter
> vectors instead of filling them with NA:
>
>> do.call("rbind",x)
>     [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    9    2    7
> [2,]   10    6    8   10    6
> [3,]    1    9    7    2    0
>
> So, I'd like to either take every element of the list and extend it
> with NAs to the length of the longest element, or rbind every element
> where missing places are filled with NAs instead of recycled values.
> Is this possible?  Of course, the solution is trivial using a loop,
> but I'm trying to avoid this.
>
> Thanks for any suggestions.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

markleeds at verizon.net

2009-Feb-12 21:05 UTC

head link

[R] Extending each element in a list, or rbind()-ing arrays of different length without recycling

Thanks Rolf. very nice but "pretty easy" is ALWAYS a relative 
statement.



On Thu, Feb 12, 2009 at  3:59 PM, Rolf Turner wrote:
> On 13/02/2009, at 9:06 AM, markleeds at verizon.net wrote:
>
>> Hi Jason: below seems to work. you have to take the transpose because
>> the apply
>> returns the rows transposed. i'm also not sure how to make the NAs
be
>> the last
>> ones but maybe someone can show us how to do that.
>
> Pretty easy:
>
> na.at.end <- function(x){
> i <- is.na(x)
> c(x[!i],rep(NA,sum(i)))
> }
>
>>
>> mat <- matrix(c(2,7,2,7,9,10,10,6,8,6,1,9,7,2,0),byrow=TRUE,nrow=3)
>> print(mat)
>>
>> t(apply(mat,1, function(.row) {
>>    .row[duplicated(.row)] <- NA
>>    .row
>> }))
>
> Then just change to:
>
> t(apply(mat,1, function(.row) {
>    .row[duplicated(.row)] <- NA
>    na.at.end(.row)
> }))
>
> 	cheers,
>
> 		Rolf
>
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Patrick Burns

2009-Feb-13 08:59 UTC

head link

[R] Extending each element in a list, or rbind()-ing arrays of different length without recycling

My question is: Why would you want a data
structure that is clearly not expressive of the
data involved?

Let me guess.  You are coming from statistical
software where data are always rectangular.


Patrick Burns
patrick at burns-stat.com
+44 (0)20 8525 0696
http://www.burns-stat.com
(home of "The R Inferno" and "A Guide for the Unwilling S
User")

Jason Shaw wrote:> Hi,
>
> I'm trying to take a matrix such as
>
>      [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    2    7    9
> [2,]   10   10    6    8    6
> [3,]    1    9    7    2    0
>
> and generate a new matrix which contains only the unique values in each
row:
>
>      [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    9   NA   NA
> [2,]   10    6    8   NA   NA
> [3,]    1    9    7    2    0
>
> My problem is that I can use apply(matrix,MARGIN=1,FUN=unique) to find
> the unique values, but this leaves me with a list with arrays of
> different length:
>
>   
>> x <- apply(peaks,MARGIN=1,FUN=unique)
>>     
> [[1]]
> [1] 2 7 9
>
> [[2]]
> [1] 10  6  8
>
> [[3]]
> [1] 1 9 7 2 0
>
> and using do.call("rbind",x) recycles the values of the shorter
> vectors instead of filling them with NA:
>
>   
>> do.call("rbind",x)
>>     
>      [,1] [,2] [,3] [,4] [,5]
> [1,]    2    7    9    2    7
> [2,]   10    6    8   10    6
> [3,]    1    9    7    2    0
>
> So, I'd like to either take every element of the list and extend it
> with NAs to the length of the longest element, or rbind every element
> where missing places are filled with NAs instead of recycled values.
> Is this possible?  Of course, the solution is trivial using a loop,
> but I'm trying to avoid this.
>
> Thanks for any suggestions.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
>

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